Noise preventing arrangement of a motor

Abstract

The present invention provides an arrangement of a motor intended to prevent transmission of vibrations, i.e., noises between a noise preventing circuit and the motor. The noise preventing circuit is formed into a unit, thereby realizing simple and automatic installation thereof into the motor without giving influences upon the vibration preventing structure of brushes. According to the arrangement, the noise preventing circuit may not be used and the specifications thereof may be easily changed.

What is claimed is: 
     
       1. A noise preventing arrangement of a motor, comprising: a housing having an open end;   an end plate mounted at the open end of the housing;   a noise preventing unit incorporated into said motor and located within said housing, said noise preventing unit including a casing and a noise preventing circuit;   said casing including a mounting portion for mounting the noise preventing circuit, a terminal connecting portion for allowing an external power source to be connected to the noise preventing circuit and a first engaging groove positioned between said mounting portion and said terminal connecting portion, said first engaging groove receiving an end part of the housing, said casing including a second engaging groove that is engaged by said end plate;   said noise preventing circuit being adapted to be received in the mounting portion of the casing, said noise preventing circuit including a choke-coil and a capacitor selectively connected to terminals located at an opening provided in said casing, said choke-coil and said capacitor being individually connectable and disconnectable from said noise preventing circuit;   a vibration preventing member disposed adjacent the end plate for preventing the transmission of vibration to said noise preventing unit;   a brush holder fixed to said end plate; and   brushes mounted on said brush holder and connected to said noise preventing circuit.   
     
     
       2. A noise preventing arrangement of a motor as claimed in claim 1, wherein said end plate to which said noise preventing unit is fixed, is fixed to said brush holder by a lock washer, said vibration preventing member being a brush that is interposed between the end plate and the brush holder, and said noise preventing circuit being connected with said brushes through a set of pigtails, so that transmission of vibrations between said brushes and said noise preventing unit is almost completely prevented. 
     
     
       3. A noise preventing arrangement of a motor as claimed in claim 1, wherein said vibration preventing member is mounted in said second engaging groove, so that transmission of vibrations from said end plate to said noise preventing unit is prevented. 
     
     
       4. A noise preventing arrangement of a motor as claimed in claim 1, wherein a connection terminal is provided in said noise preventing circuit of the noise preventing unit, while a coupling electrode is formed in said brush holder, said connecting terminal being connected with said coupling electrode when said noise preventing unit is mounted to said end plate. 
     
     
       5. A noise preventing arrangement of a motor as claimed in any of claims 1, 2, 3 or 4, wherein said noise preventing circuit of the noise preventing unit is selectively provided with at least one of a choke coil and a capacitor. 
     
     
       6. A noise preventing arrangement as claimed in any of claims 1, 2, 3 or 4, wherein said noise preventing circuit of the noise preventing unit is with only a terminal for connection to an external power source so that said noise preventing circuit is not used since said terminal is connected to said brushes when said noise preventing unit is mounted into the motor. 
     
     
       7. A noise preventing arrangement of a motor as claimed in any of claims 1, 2, 3 or 4, wherein said noise preventing circuit is mounted to said noise preventing unit only by being pressed into said casing from one direction, and a protecting cover is mounted from the same direction after said noise preventing circuit is mounted. 
     
     
       8. A noise preventing arrangement of a motor as claimed in any of claims 1, 2, 3 or 4, wherein said casing of the noise preventing unit is fixedly positioned by being engaged with said end plate of the motor from one direction. 
     
     
       9. A noise preventing arrangement of a motor as claimed in claim 1, wherein said second engaging groove is formed on the mounting portion of the casing. 
     
     
       10. A noise preventing arrangement of a motor as claimed in claim 1, including an opening section and at least one housing part which are formed in the mounting part of the casing, said opening section being adapted to receive the capacitor and said housing part being adapted to receive the choke-coil.